Improved performance of Mn3O4-based nanocomposites in photocatalytic removal of methylene blue

In the present work, the ultrasonic-assisted co-precipitation method was applied to synthesize pure Mn3O4, Samarium-doped Mn3O4, and Zirconium-doped Mn3O4. Furthermore, as an additional stage, the hydrothermal method was utilized to prepare zeolite 4 A exploiting a natural zeolite (clinoptilolite). Afterward, some of the prepared Mn3O4-based photocatalysts were immobilized using the synthesized zeolite 4 A as a proficient support, resulting in the synthesis of some novel Mn3O4-based nanocomposites (including Sm(0.02)-Mn3O4/Zeolite 4 A and Zr(0.02)-Mn3O4/Zeolite 4 A). X-ray diffraction (XRD), Diffuse Reflectance Spectroscopy analysis (DRS), Scanning Electron Microscopy (SEM) as well as Energy Dispersive X-Ray Spectroscopy (EDX) were the techniques utilized for the characterization of the prepared samples. The XRD patterns of the doped Mn3O4 samples validated the presence of Hausmannite structure, excluding any impurities. Eventually, to evaluate the photocatalytic performance of synthesized photocatalysts, methylene blue (MB) aqueous solution as an organic pollutant was chosen to study. According to the results, Sm(0.02)-Mn3O4/Zeolite 4 A nanocomposite and Zr(0.1)-Mn3O4 nanoparticles revealed an outstanding photocatalytic efficiency of 95. 5% and 98.4% in photocatalytic removal of MB in the 210 min, respectively. •Mn3O4 nanoparticles was prepared by ultrasonic-assisted co-precipitation.•Improvement of photocatalytic activity was performed by supporting and doping.•The type and molar ratio of dopant affects the photocatalytic activity of Mn3O4.•Photocatalytic activity of zeolite-based composites can be affected by the dopant.•The Zr(0.1)Mn3O4 sample exhibited the best photocatalytic efficiency.